This invention relates generally to sealing of gas leakage flow across a piston of a piston type compressor.
In more particular aspects this invention relates to sealing of an area subjected to a high as pressure differential by introducing across the gas leakage flow an intermediate zone of viscous liquid, subjected to pressure higher than gas pressure, permitting very small leakage of the viscous liquid into the gas compression chamber and completely preventing any gas leakage.
In still more particular aspects this invention relates to hydraulically driven free piston type gas compressor, the compression stages of which are sealed by the hydraulic liquid at the pump working pressure, greater than the compression pressure.
Sealing of compressor piston presents a difficult problem. Due to very low viscosity of gas, leakage even through very small clearances becomes very large, especially when leakage flow is induced by a high pressure differential. Also because of very low lubricity of the gas, conventional elastomer, self-energizing type seals, are subjected to a high rate of wear.